Department of Agriculture and Fisheries
Biosecurity Queensland
Restricted invasive plant
Pond apple
Annona glabra
Pond apple is a major environmental weed of the Wet
Tropics bioregion of Far North Queensland and a Weed
of National Significance. Small infestations occur in
South-East Queensland. This small to medium size
tree forms dense stands, particularly in swamp areas.
Pond apple invades fresh, brackish and saltwater
areas and its thickets are capable of replacing whole
ecosystems. Its seed is primarily dispersed by water,
especially during floods. Disturbed flood-prone
ecosystems are most at risk from pond apple invasion,
particularly mangroves, melaleuca woodlands, riparian
areas, drainage lines, coastal dunes and islands.
Pond apple currently covers around 2000 ha of the
Wet Tropics bioregion in Queensland; there are also
isolated occurrences on the eastern coast of Cape York. Its
potential to spread throughout coastal regions of tropical
and subtropical Australia is considerable. Dispersal of
fruit and seed by water and animals allows pond apple
to be easily spread within and between catchments.
Unlike many weeds, pond apple has an alarming ability to
invade relatively undisturbed areas. Pond apple is also a
pioneering plant and will opportunistically invade areas
after disturbances such as cyclones and floods.
Pond apple (also known as cherimoya) is a native tree of
tropical North, Central and South America and West Africa
where it occurs in fresh and brackish swamplands.
Originally introduced to Australia as grafting stock for
commercially grown custard apple in 1912 and still
remains as a root stock in old orchards, pond apple has
become a serious weed in Queensland with the potential
to spread throughout northern Australia as such it is listed
as a Weed of National Significance.
Legal requirements
Life cycle
Pond apple is a restricted invasive plant under the
Biosecurity Act 2014. It must not be given away, sold, or
released into the environment without a permit. The Act
requires everyone to take all reasonable and practical
steps to minimise the risks associated with invasive
plants and animals under their control. This is called a
general biosecurity obligation (GBO). This fact sheet gives
examples of how you can meet your GBO.
Trees begin to flower and produce fruit when they are at
least two years old. The main flowering period in the
Wet Tropics is from December to February with fruit
formation following in January to March. From February
to April the fruit falls from the tree and matures on the
ground. Sporadic flowering and fruiting can also occur at
other times of the year.
At a local level, each local government must have a
biosecurity plan that covers invasive plants and animals
in its area. This plan may include actions to be taken on
certain species. Some of these actions may be required
under local laws. Contact your local government for
more information.
Description
Pond apple is a semi-deciduous tree that can reach about
12–15 m in height; however, it typically grows to 3–6 m.
Pond apple individuals are usually single-stemmed, but
when seeds germinate in groups the resulting plants have
a multi-stemmed appearance. Over time these stems may
fuse together, giving the appearance of a single plant.
However, each original stem maintains its own sap
stream, which can complicate control when herbicide
injections are employed as each individual stem must
be injected. Young pond apple plants often have stems
with swollen bases. Mature plants may develop slightly
buttressed roots.
Stems of pond apple are softwood with a thin grey bark
bearing prominent lenticels (pores). Lenticels are involved
in gas exchange and appear on the stem as small raised
structures of cork-like composition. Native mangroves
also have lenticels, so care should be taken during
identification.
The leaves of pond apple are alternate, 7–12 cm long and
have a prominent midrib. The upper surface of the leaves
varies from light to dark green depending on the age of
the plant. Leaves are paler on the underside and there
is a distinctive small fold where the leaf blade joins the
leaf stalk. The leaves emit a distinct smell (similar to the
smell of green apples) when crushed—another feature that
can distinguish pond apple from mangroves. In the dry
season, the more mature leaves yellow and this can aid in
detecting pond apple infestations.
Flowers, short-lived and rarely noticed, are 2−3 cm in
diameter, pale yellow to cream, and consist of three
leathery outer petals and three smaller inner petals. The
inner base of the flower is bright red in colour.
The fruit is spherical, about 5–15 cm in diameter and green
in colour. Fruit have the appearance of a smooth-skinned
custard apple. The ripe fruit falls from the tree when
yellow/orange, and turns black on the ground. The flesh
turns orange at maturity. Each fruit contains 100–200
seeds that are similar in size and shape to pumpkin seeds.
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Pond apple Annona glabra
Both fruit and seed can float and remain viable for many
months in fresh to saline water and germination can
occur in fresh or brackish situations. The success of
seed dispersal can be attributed to the fruiting period
coinciding with the wet season when flooding is common.
Ocean currents also play a role in transporting seed along
the coast and seed can germinate above high tide level
when deposited during flood events or tidal surges.
Pond apple seeds are relatively short-lived and when
conditions are suitable, seed banks can be rapidly
depleted through mass germinations within six months of
fruit fall. Few pond apple seed survive for longer than one
year, with the seed bank completely depleted within three
years, provided that no new seed input occurs.
Pond apple is opportunistic and tends to establish in
disturbed areas affected by floods or cyclones, but it can
also establish in relatively undisturbed environments.
While seedlings need light for rapid growth they can
remain dormant in semi-shaded conditions until a gap
in the canopy is created.
Methods of spread
Although generally spread by water, seed can also be
disseminated by feral pigs, wallabies, cassowaries and
other fruit-eating animals.
Some plants may exist where they were used for custard
apple grafts but the orchard has being abandoned and the
pond apple reverted to form.
Habitat and distribution
Pond apple requires moist soil with regular inundations
of fresh to brackish water. It can withstand periods
of flooding, with its roots under water for weeks at a
time; however, it does not appear to survive permanent
inundation.
In Australia, pond apple is invading a wide range of
habitats such as:
• creeks, riverbanks and floodplains
• wetlands, including melaleuca and pandanus swamps
and sedge lands
• mangrove communities and beach high-tide litter
zones
• rainforest areas
• dams
• agricultural drainage systems.
In particular, melaleuca wetlands and Heritiera littoralis
mangrove communities are at risk.
Over 2000 ha of the Wet Tropics bioregion of Far North
Queensland are currently covered by pond apple.
Major infestations occur between Cardwell and Cooktown,
but pond apple has also been found as far south as
Brisbane and northern New South Wales and north to Cape
York and the Torres Strait.
Predictive modelling programs have identified that areas
most at risk of invasion include the north-eastern side of
Cape York, the Gulf of Carpentaria river systems, the top
end’s wetland areas (including Kakadu) and the coastal
strip from Cape York to Brisbane.
Control
Managing pond apple
The GBO requires a person to take reasonable and
practical steps to minimise the risks posed by pond apple.
This fact sheet provides information and some options for
controlling pond apple.
The best time of year to undertake control of pond apple is
during the dry season (August to November) when access
to waterways and wetlands is easier. Control work should
start at the top of the catchment or the uppermost section
of the creek, river or waterway. This will reduce the risk of
seed being transported into clean or previously treated
areas downstream.
Control methods for pond apple include mechanical
control, herbicide control and fire. Often a combination
of methods can be used to achieve effective control.
Follow-up treatment is essential to identify missed plants,
regrowth and any problems with the initial control method.
When choosing control options consider size and density
of infestation, accessibility, safety hazards, presence of
non-target species, life cycle stage of the plant, and the
time of year.
Prevention
The two most cost-effective methods of managing
pond apple are the prevention of infestations and early
intervention. While prevention is the best way to control
weeds, this is not always possible as natural means,
such as floods and animals, easily disperse seed. New
infestations must therefore be quickly identified and
controlled before they become widespread.
Mechanical control
Mechanical options for clearing pond apple infestations
include hand pulling, chain pulling and dozer pushing.
These methods (except hand pulling) are only suitable on
flat country; in areas free of sensitive vegetation; where
machines can manoeuvre easily; and where the risk of soil
erosion is low. Ensure that the roots of uprooted trees are
not in contact with soil or plants may resprout.
Fire
Pond apple is very susceptible to fire. For control using
fire, sufficient fuel is required. Unfortunately this is not
often available in dense pond apple infestations. When
using fire the entire circumference of the plant must be
burnt to effectively kill pond apple. Depending on its
intensity, a fire can destroy seeds lying on the ground but
seeds in cracks or on moist soil, where fire will not burn,
can remain viable. Follow-up work is therefore required to
control seedlings that germinate following fire.
Herbicide control
Herbicides can be applied to pond apple when it is
actively growing in a number of ways. Stem injection is
recommended for aquatic areas as it minimises herbicide
run-off and off-target impacts.
There are two ways to achieve stem injection. The axe cut
method involves making horizontal cuts into the sapwood
around the circumference of the stem, as low to the ground
as possible. While still in the cut, lean the axe out to make
a downward angled pocket in which herbicide is injected.
A double row of cuts, with the second row placed under
the spaces created by the first row, is recommended for
maximum kill rate.
The drill and fill method involves drilling downward
angled holes, 5 cm apart around the circumference, with a
powered drill. Herbicide is then immediately injected into
the holes.
Stem injection is not generally suited to larger trees due
to the number of cuts/holes required. It is also difficult to
control multi-stemmed trees where each separate stem
requires treatment.
The basal bark application method involves spraying
or painting a herbicide and diesel mix around the
circumference of the stem, from ground level up to
50 cm. This is a rapid method of control in areas with
large monocultures of pond apple where off-target
vegetation will not be affected. It should not be used
in aquatic situations for both environmental and
effectiveness reasons.
Foliar application or the overall spray method is useful for
dense monocultures of young plants up to 1 m tall where
there is no risk of damaging native vegetation.
Table 1 lists the herbicides registered or permitted for
control of pond apple. Permit number PER12139 expires
30 June 2020.
Herbicides must be used with care; therefore, before use:
• ensure all permit conditions are met
• read instructions and conditions for use on
the label
• consider possible impact on non-target vegetation and
surrounding environment
• adhere to individual product label grazing withholding
periods and restraints for treated areas.
Further information
Further information is available from your local
government office, or by contacting Biosecurity
Queensland on 13 25 23 or visit
www.biosecurity.qld.gov.au.
Pond apple Annona glabra
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Table 1. Herbicides for the control of pond apple
Situation
Herbicide
Rate
Registration
details
Comments
1.67 L
product per
100 L of
diesel
PERMIT
13684
333 g/L fluroxypyr
(e.g. Starane
Advanced®)
900 mL
product per
100 L of
diesel
360 g/L glyphosate
(e.g. Roundup
Biactive®)
500 mL
product per
1 L of water
Starane
Advanced is
registered for
basal bark
application
Basal bark: DO NOT apply to trees growing in a water body.
Basal bark plants with stems up to 20 cm basal diameter. Ensure
all stems on multi-stemmed plants are treated. Spray the bark
around the stems from the ground level to a minimum height of
50 cm wetting thoroughly to allow the spray mix to soak through
the bark.
Riverbank areas 120 g/L picloram +
240 g/L triclopyr
Swamp areas
(e.g. Access®)
Irrigation
channels
Dams
Enclosed water
bodies
Coastal areas
Fence lines
200 g/L triclopyr +
100 g/L picloram
®
Non-agricultural (e.g. Conqueror )
areas, public
lands, and
rights-of-way
Pastures
250 g/L imazapyr
(e.g. Unimaz®
250 SL)
100 mL
product per
1 L of water
800 mL
product per
100 L of
water
Expires June
2020
Refer to
product label
DO NOT treat wet stems with basal bark mix as this can repel the
diesel mixture.
Stem injection: Cuts should be made at waist height. To make
an injection pocket at waist height, use a ¾ length axe with a
blade width of 5–7 cm. The cut of injection must be through the
bark and deep enough to place the herbicide in contact with the
sap wood. The herbicide must be applied immediately after the
dose pocket is made. Apply herbicide with an applicator fitted
with a tree injector kit which can be accurately calibrated. Set
the vaccinator to deliver 1 mL of prepared solution per cut. Space
cuts at 13 cm centres around tree. When treating trees less than
the width of the axe, ensure herbicide does not run out of the
sides of the cut. This can be overfcome by using the corners of
the axe to make the pocket.
Overall spray: DO NOT spray past the point of runoff. Ensure
thorough spray coverage of all foliage. Incomplete coverage will
result in regrowth. Apply to actively growing plants up to early
flowering. Avoid spraying when plants are stressed or fruiting.
Repeat spray application when re-infestation occurs.
DO NOT apply to plants in water. Lower the water level to expose
the weed infested band, before application.
DO NOT allow spray to drift to nontarget vegetation. Maintain a
distance of at least 10 m to nontarget terrestrial vegetation.
A spray shield should always be used.
DO NOT apply more than two applications per year, six months
apart.
Treated dams should not be allowed to overflow. DO NOT use
foliar spray application where dams may overflow.
Apply as close as possible from the foliage. A distance of not
greater than 30 cm is recommended.
DO NOT apply directly or allow drift onto water.
Apply at 200 g imazapyr/100 L of water, to a maximum volume
of 1500 L/ha.
Spot spray the weed using handheld equipment at low pressure
(≤ 250 kPa/2.5 Bar) to produce a coarse to very coarse spray.
DO NOT spray if rainfall or elevated waterflow are expected
within 48 hours of application.
DO NOT apply to trees greater than 2 m in height.
Stop spraying before the herbicide droplets on the leaves begin
to coalesce and run off.
DO NOT apply under meteorological conditions or from spraying
equipment which could be expected to cause spray to drift onto
wetlands, natural surface waters, soil, neighbouring properties
or other sensirive areas.
Avoid soil contamination – DO NOT spray past the point of runoff.
It is a requirement of the permit that all persons using the products covered by this off-label permit read and comply with the details and conditions listed
in the permit. In addition, read the herbicide label carefully before use and always use the herbicide in accordance with label directions unless otherwise
stated in the permit.
Read the label carefully before use. Always use the herbicide in accordance with the directions on the label.
This fact sheet is developed with funding support from the Land Protection Fund.
Fact sheets are available from Department of Agriculture and Fisheries (DAF) service centres and our Customer Service Centre (telephone 13 25 23). Check our website at
www.biosecurity.qld.gov.au to ensure you have the latest version of this fact sheet. The control methods referred to in this fact sheet should be used in accordance with the
restrictions (federal and state legislation, and local government laws) directly or indirectly related to each control method. These restrictions may prevent the use of one or
more of the methods referred to, depending on individual circumstances. While every care is taken to ensure the accuracy of this information, DAF does not invite reliance
upon it, nor accept responsibility for any loss or damage caused by actions based on it.
© The State of Queensland, Department of Agriculture and Fisheries, 2016.
07/16